How create a desert like this in Blender?
For youre purpose you could use the Landscape add-on (Preferences -> Add-ons -> Categories/Add mesh -> ANT Landscape) or the Ocean generator in Blender. The Ocean modifier might work the best because you want such sharp dune cresps and a desert is very similar to an ocean cause it is influenced by wind just like oceans. Add a plane to the scene and add the ocean modifier. Play around with the settings until you are satisfied. Use the "Choppine" slider to sharpen the cresps and the scale to adjust the height of the dunes. Leave the Resolution at a value around 10. You don't want to much detail in that scene. Now you have got the basic shape of the desert. 

The secret to make it looks very realistic is the texturing. I don't know how far you are in that but you will definitely need a so called "bump map" for the shape of the small grooves on the dune slope.